Attenuation limit of silica-based hollow-core fiber at mid-IR wavelengths

Fei Yu, Peng Song, Dakun Wu, Tim Birks, David Bird, Jonathan Knight

Research output: Contribution to journalArticle

Abstract

We study the mid-infrared attenuation of antiresonant hollow-core fiber made of fused silica glass. The role of absorptive losses increases with wavelength but can be minimized by reducing the overlap of the trapped light with the silica. We show that this overlap is least at the lowest-order antiresonance condition, corresponding to the thinnest core wall, and for higher resonances scales with the core wall thickness. A record-low minimum attenuation of 18 dB/km measured in our fiber at 3.1 μm wavelength is not limited by silica absorption. We measured 40 dB/km attenuation at 4 μm wavelength, where the attenuation of bulk silica is 860 dB/m. We show that this corresponds to a modal overlap of 2.81 × 10-5 which is in good agreement with simulations, suggesting that at this wavelength, attenuation is limited by silica absorption. This enables us to predict the achievable attenuation at longer wavelengths as well. Extrinsic losses due to gaseous molecular absorption may make demonstration of such losses difficult in some spectral bands. In contrast to shorter wavelengths, where leakage loss is the primary attenuation mechanism, introducing additional elements into the cladding design is unlikely to reduce the attenuation further, and further loss reduction would require a larger core size.

Original languageEnglish
Article number080803
JournalAPL Photonics
Volume4
Issue number8
Early online date12 Aug 2019
DOIs
Publication statusE-pub ahead of print - 12 Aug 2019

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Computer Networks and Communications

Cite this

Attenuation limit of silica-based hollow-core fiber at mid-IR wavelengths. / Yu, Fei; Song, Peng; Wu, Dakun; Birks, Tim; Bird, David; Knight, Jonathan.

In: APL Photonics, Vol. 4, No. 8, 080803, 12.08.2019.

Research output: Contribution to journalArticle

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